How do you bind the value of the HTML element with a C# property in Blazor?

You have to use the bind attribute to reflect the DOM element value in the C# property.

<p>
    @* This is the input element *@
    Enter your name: <input type="text" @bind=@name />

    <button @onclick="@PrintName">Print Name</button>
</p>

@code {
    string name;

    private void PrintName()
    {
      Console.WriteLine(name); // Here the entered name will be printed.
    }
}